Drilling implement



Jan. 30, 1945 R. D. ZIMMERMAN DRILLING IMPLEMENT Filed Sefit. 14-, 1942 I 9 :5 as- INVENTOR fiobez'fflzimrmqn ms" ATTORNEY.

part pointed out hereinafter.

Patented Jan. 130, 19 5' H. Y., a corpora A pplicationleptember 14, 1942, Serial No. 458,217

2 ohm.

This invention relates to cutting tools, and more particularly to a drilling implement adapted to be actuated into the work by a rock drill and having a passage for'conveying cleansing fluid into the hole being drilled,

In the drilling of rock it is essential that an ample supply of cleansing fluid, as for example water, he directed to the working face to both remove the cuttings as rapidly as they are formed and to maintain the temperature of the cutting end of the drilling implement to a low value. It is for this reason that drilling implements are usually provided with a hole extending axially therethrough to the inne ends of the spaces be- .tween the cutting wings of the implement. In

certain structures an additional hole is extended 'from the axial hole tothe side surface of the working implement to direct a separate stream of water toward the side of the drill hole to facilitate the removal of the cuttings.

' Normally, when the material being drilled is of a uniformly hard nature it breaks evenly across the entire working surface and no unbroken por ment constructedin accordance with the Practice .of the'invention,

Figure/2 is an end view of the drilling implement, and

Figure 3 is an elevation taken through Figure 2 on the line 3-! looking in the direction indi-- cated-by the arrows.

designates a drilling implement comprising, in the present instance, a drill bit 2| of the detachable type which is threadedly connected to a rod 22 through which the force of a suitable drilling mechanism (not shown) istransmitted to the drill bit 2L The rod 22 and the drill bit have axialpassages 23 and 24, respectively, for conveying water or pressure fluid, or both, to the cutting edges 25 tions of rock project from the bottom of the drill hole to interfere seriously with the flow of water through the drilling implement, There are instances, however, where deposits of soft material,

clay for example, are located in the line of drilling and in such case a core of clay rises, often. to a considerable height, in the axial hole and cuts off the flow of water to the drill hole. In known structures in which the axial passage is of substantially uniform diameter throughout its length such core will, in many instances, also seal the inlet end of the branch passage and prevent the .water from reaching thev drill hole through the latter channel.

It is accordingly an object of the invention to assure the delivery of cleansing fluid to the drill hole irrespective of the nature of the material being drilled.

ferent diameter.

A more specific object is to so construct the drilling implement that a core of material entering and clogging the axial passageway of a drilling implement will be of insuillcient cross-secof the drill bit, and in the drill bit is a branch passage 26 that leads from the passage 24 to the periphery of the drill bit, preferably at a point rearwardly of and adjacent the cutting teeth 21 carrying the cutting edges 25. In order to assure the delivery of an ample supply of water to all the spaces 28 between the cutting teeth 21 a recess 29 is formed in the front end of the drill bit to communicate with all: the spaces 28,

In accordance with the practice of the invention, the passage 24 is formed of portions of dif- The rearmost, and larger, of such portions designated 30 is preferably of the same diameter as the passage 23, and it is into this enlarged portion 30 that the branch passage 26 opens. The portion 31 of the passage 24 lying terial, such as clay, passes through the restricted portion 3| into the enlarged portion 30 a suitable space will at all times exist between such core and the wall of the-enlarged portion 30 to permit the free passage of water into the'branch passage 26.

In practice, whenever a-plug 'of soft material of the diameter determined by the reduced portion 3| enters the enlarged portion 30 or, for that matter, the passage 23 in the rod, suflicie'nt flow area will exist in these passages to assure an ample delivery of water to the branch passage 26 and thus to the drill hole. Normally, however, the water flowing through the enlarged portion 10 to the branch passage has an erosive effect upon the core which seldom rises to any considerable distanceabove the reduced or die portion 3| so that the same flow area will exist at the Figure 1 is a side elevation of a drilling impleto point of communication of the enlarged Portion Referring more particularly to the drawing, 20

entering the passage of a smaller diameter than 10 the passage.

2. A drilling implement, comprising a body having cutting teeth at one end and a passage for conveying cleansing fluid to the cutting teeth, said passage having a branch leading to and opening into the periphery of the body, and a surface in the passage to maintain the diameter 01' a core of material entering the passage smaller than the diameter of the passage.

ROBERT D. ZIMJQERMAN. 

